Wireless carriers throttle video apps at varying rates, researchers claim

New research, again based off Wehe test results, indicates wireless carriers are throttling video content, regardless of location or time of day, and that different apps are impacted at varying rates.

Researchers from the University of Massachusetts Amherst and Northeastern University analyzed more than 620,000 crowd-sourced measurements taken in the U.S. from the Wehe app during January and May 2018 and January 2019.  

The results showed different carriers throttle various video apps at different rates.

The study detected T-Mobile throttled Amazon Prime (51% of the time), NBCUniversal (64%), Netflix (61%) and YouTube (67%), but Vimeo was throttled only 5% of the time, and Skype not at all during tests. The researchers also found that T-Mobile’s policy of throttling based on bytes differs between apps, with the study detecting 7 MB of delayed throttling for Netflix and NBC Sports, 6 MB for Amazon Prime, and no delayed throttling for YouTube, which is throttled from the start.

AT&T meanwhile didn’t appear to throttle Amazon Prime, Skype or Vimeo video content at all, but Netflix was throttled during 70% of tests and YouTube 74%. Verizon was found to throttle at two different rates, 2 Mbps and 4 Mbps, which the researchers attributed to different plans such as the Beyond Unlimited plan which allowed HD-quality streaming of 720p.

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It should be noted that the researchers acknowledged that the dataset doesn’t include information about service plans, including tiers that don’t restrict video streaming or allow users to downgrade video resolution. Most operators offer unlimited data pricing plans that have different video throttling policies based on how much consumers pay.  AT&T’s Stream Save, for example, which when enabled caps video data speeds at 1.5 Mbps or generally equivalent to Standard Definition quality of about 480p.

The researchers also found that while throttling does limit video resolution, the default settings in the video streaming apps, such as Netflix and Amazon, are a significant cause for lower-quality streaming resolution.

One of the study’s authors, David Choffnes, associate professor at Northeastern University, told Bloomberg that differences in throttling various video services could be caused by errors since carriers can’t detect and limit some video apps after technical changes have been made.

To make things fair, carriers may try to throttle all video, but are unable to dictate how content providers deliver video, Choffnes told the news outlet. “Then you have certain content providers that get throttled and some that don’t,” he said.

While carriers have previously acknowledged that they may slow speeds during times of network congestion or to manage traffic efficiently, Choffnes indicated the throttling rates were observed around the clock, and not just during peak times of use.

RELATED: Verizon, AT&T, T-Mobile and Sprint face throttling questions from senators

“They are doing it all the time, 24/7, and it’s not based on networks being overloaded,” Choffnes told Bloomberg.

The Federal Communications Commission in late 2017 decided to rollback so-called net neutrality rules, and reclassified internet service providers so that were no longer bound by Title II regulations put in place in 2015. It’s not illegal for carriers to throttle users or specific apps but service providers are supposed to disclose any such practices to the public.

Throttling concerns and controversy over results from the Wehe testing platform itself are not new. Senators last year raised questions about data-throttling practices of the nation’s four top carriers, following publication of earlier research based on tests from Wehe platform.

CTIA in October 2018 posted a blog in response to concerns over network management, and how Wehe app detects variations.

“The Wehe app compares the data speeds that consumers experience with and without that content provider metadata. If the Wehe app detects a difference in speed, it registers this as ‘differentiation’ and implies this is a violation of ‘net neutrality,’” wrote CTIA CTO Tom Sawanobori. “What the Wehe app is really detecting is either basic wireless network management (based on consumer choice) or data management practices used by content providers. That’s because content providers have data practices in place—outside the control of providers—that reduce video resolution of data traffic flowing through their sites or apps depending on the consumer’s mobile device.”